PROJECT SUMMARY Dr. Xiaoyang Zhang is a postdoctoral research fellow in the laboratory of Dr. Matthew Meyerson at Dana- Farber Cancer Institute and the Broad Institute. His long-term career goal, in alignment with the mission of the NCI, is to reduce cancer-associated mortality and suffering by determining mechanisms of cancer development and identifying attractive therapeutic targets. To accomplish this goal, Dr. Zhang uniquely leverages both genomics and cellular and molecular biology methods to answer fundamental questions relating to cancer biology. Large-scale genomic surveys of human cancer have recently found two types of genomic alterations of the KLF5 gene. Dr. Zhang identified that a non-coding region, nearby the KLF5 gene and filled with super- enhancers, is focally amplified in several cancer types and the amplification correlates with KLF5 over- expression. In addition, Dr. Meyerson's laboratory identified significant hot-spot mutations in the DNA binding domain of the KLF5 gene in non-small cell lung cancers. All these strongly suggest that KLF5 is a novel oncogene. This proposal aims to characterize the role of these genomic alterations in regulating KLF5 activity and promoting tumorigenesis. Aim 1 will study the link between the super-enhancer amplification and KLF5 over-expression, and the oncogenic consequences of KLF5 over-expression in diverse cancer types. Then, Aim 2 will study the oncogenic function of KLF5 hot-spot mutations by using isogenic KLF5 wild-type and mutant cell lines generated by genome-editing tools. Finally, in Aim 3, a CRISPR-mediated promoter/enhancer screening will be developed to identify the functional binding sites of KLF5 mutants and their associated target genes and pathways. The proposed research will improve our understanding of how oncogenic transcription factors promote cancer development and may yield novel therapeutic targets. Dr. Zhang will gain more research training in biostatistics, computational biology and genome-editing, and simultaneously enhance his career development through training in grant-writing and leadership. The outstanding research environment and facilities available to Dr. Zhang include laboratory space and full institutional access at both Dana-Farber Cancer Institute and the Broad Institute. During the K99 phase, Dr. Zhang's research and training will be carried out under the primary mentorship of Dr. Matthew Meyerson, a leader in cancer genomics, and will be additionally enhanced by collaborations with experts in computational biology and high-throughput genetic screening, as well as by mentoring from an advisory committee consisting of Drs. Myles Brown, Bradley Bernstein, Feng Zhang, and Levi Garraway.